#include <stdio.h>
int main()
 {   //1.变量只能存1个值
    int a =20;
    printf("%d\n",a);

    a=10;
    printf("%d\n",a);

    //2.变量名不能重复
    int a=20;
    printf("%d\n",a);

    //3.一条语句可以定义多个变量
    int x = 10,y = 20 ,z = 30;
    printf("%d\n",x);
    printf("%d\n",y);
    printf("%d\n",z);

    //变量的使用一定要赋值
    int f;
    printf("%d\n",f);
}



